Growth and nanofabrication of all-perovskite superconducting/ferromagnetic/superconducting junctions

Andrés Prada, Roberto de; Golod, T.; Bernhard, Christian; Krasnov, V. M.

doi:10.1007/s10948-019-5023-6

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Journal article

Growth and nanofabrication of all-perovskite superconducting/ferromagnetic/superconducting junctions

Andrés Prada, Roberto de Department of Physics, Stockholm University, Albanova University Center, Stockholm, Sweden - Physics Department and Fribourg Center for Nanomaterials (FriMat), University of Fribourg, Switzerland
Golod, T. Department of Physics, Stockholm University, Albanova University Center, Stockholm, Sweden
Bernhard, Christian Physics Department and Fribourg Center for Nanomaterials (FriMat), University of Fribourg, Switzerland
Krasnov, V. M. Department of Physics, Stockholm University, Albanova University Center, Stockholm, Sweden

01.09.2019

Published in:

Journal of Superconductivity and Novel Magnetism. - 2019, vol. 32, no. 9, p. 2721–2726

English We fabricate and study experimentally all-perovskite-oxide superconductor/ferromagnetic insulator/superconductor (S/FI/S) tunnel junctions made out of the high-temperature cuprate superconductor YBa2Cu3O7−y (YBCO) and the colossal magnetoresistive manganite LaMnO3 (LMO) in the ferromagnetic insulator state. YBCO/LMO/YBCO heterostructures with different LMO thicknesses (5, 10, and 20 nm) are grown epitaxially via pulsed laser deposition. Nanoscale S/FI/S junctions with sizes down to 300 nm are made by three-dimensional nano-sculpturing with focused ion beam. Junctions with a thick (20 nm) LMO barrier exhibit a large negative magnetoresistance below TCurie∼160 K, typical for colossal magnetoresistive manganites, as well as a kink in the current-voltage characteristics at large bias (V∼1–2 Volts), attributed to Zener-type tunneling. However, they do not show a measurable Josephson current. On the contrary, junctions with the thinnest 5- nm LMO barrier exhibit a large supercurrent and no signs of magnetism. The latter may indicate the presence of pinholes due to thickness inhomogeneity and/or a ∼ 2 nm dead magnetic layer at the YBCO / LMO interface caused, e.g., by interdiffusion or strain. The junction with an intermediate 10-nm LMO barrier exhibited a desired S/FI/S junction behavior with significant negative magnetoresistance and signatures of a small Josephson current.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

Language